Hubble space telescope observations of the SN 1987A triple ring nebula

Christopher J. Burrows, John Krist, J. Jeff Hester, Raghvendra Sahai, John T. Trauger, Karl R. Stapelfeldt, John S. Gallagher, Gilda E. Ballester, Stefano Casertano, John T. Clarke, David Crisp, Robin W. Evans, Richard E. Griffiths, John G. Hoessel, Jon A. Holtzman, Jeremy R. Mould, Paul Scowen, Alan M. Watson, James A. Westphal